Fuse cut-out



May 25, 1937. B. R. HERMANN FUSE CUT-OUT Filed Feb; 27, 1936 Inventor: I

Benjamin FR. Hermann, y Hvs Attorney.

latentecl May 25, 1937 I Benjamin B. Hermann,

to General Electric Company,

New York Pittsfield, Masa, assign'or a corporation of- Application February ZI. 1936, Serial No. 65,994

9 Claims.

The present invention relates to an electric cutout, particularly of the type incorporating a fuse with mechanism capable of functioning automatically upon operation of the fuse to effect movement of the fuse from its normal position connected between stationary contact terminals to a position giving positive indication of the fuse operation.

An important object of the invention is the pro- 1 vision of improved operating mechanismfor a cutout of the type above indicated which mecha: I

nism can be adapted to function upon operation of the fuse either to effect movement of the fuse to an indicating position without total disconnecdisconnection thereof from the stationary terminals without arcing at the terminals.

Another object of the invention is the provision of improvements in the structure of a fuse cutout which .render it sturdy as well as eflicient and dependable in operation under all service conditions.

Other objects and the details of the constructions of the parts thereof when the fuse is latched.

in its normal connected position;

Fig. 2 is a side elevation of the cutout partially 35 cut away'to show the manner in which the cutout can be adapted to give only indication upon operation of the fuse and to show the positions assumed by the parts when the time has moved to its indicating position;

40 V Fig. 3 is a side elevation partially cut away to .show the cutout as adapted for complete dropout and showing a step in the operation of the cutout intermediate the indicating position and the totally dropped out or disconnected position;

Fig. 4is a partial side view of the cutout par-. tially cut away to show the parts thereof when the fuse is in its totally dropped out position, and

Fig. 5 is a detailed perspective view of the imr r proved supporting and operating mechanism of the cutout.

Referring to the drawing, l0 indicates'a housing of porcelain or similar insulating material having an integrally formed electric creepage barrier l0 3 which is disposed between the stationary contacts H and I2 carried by the housing. These stationary contacts are adapted to have line conductors fastened thereto by means of clamping screws H and I2 respectively. A cover I3 is provided for 60 the housing IQ and is mounted on the fuse l4 of tion of the fuse from the stationary contact terminals or to effect dropout of the fuse and total thecutout by means of the projections l and iii .of insulating material formed integrally with the cover and-provided with openings for accommodating the fuse.

Fuse I4 is of the expulsion type and consists of a fuse tube ll of insulating material having a contact cap-l8 secured to its upper end and enclosing a fuse link, the upper end of which link is v connected to contact cap l8 and the lower end of which has a conductor extending out from the bottom of the fuse tube.

When. the fuse I4 is in its normal connected positionillustrated in Fig. 1, cover I3 is arranged to substantially completely close the opening in the side of the housing Ill to protect the parts of the cutout from weather conditions,and contact cap I8 is arranged to engage a contact finger 2| which is carried by the upper stationary contact v H. Contact finger 2| is backed up by a spring strip 22' to providethe desired contact pressure and is formed with a downwardly facing concave seat 23 which serves as a latch to prevent outward swinging of the upper end of the fuse.

Fuse l4 and the, cover l3. carried thereby are supported in the housing In by means of a toggle mechanlsm, one lever arm or element 24 of which is hingedly supported on hinge pins 25 carried by projections 25 which are secured to the housing, and the other arm or element 26 of which is pivotally connected in a manner to be described to the element 24. Element, 24 is pivotally connected also to an element 28 which isrigidly attached to the lower end of fuse tube II. A tension spring 21 is connected between the two arms 24 and 26 and tends to effect collapse of the toggle mechanisrh. A stop 29 which is formed integrally with cover I3 cooperates with projection l6 to hold the element 28 therebetween and allow only a small amount of relative movement between the fuse tube and cover.

The details of thesupporting mechanism are shown more clearly in Fig. 5 from which it will be seen that element 24 of the toggle mechanism comprises a. pain pf members 30 which are held in rigidly spaced apart relation by means of bracing members 3| and 32 and strap 33 and are provided with hook-shaped portions 34- for supporting the members on hinge pins '25. Thougho'nly one hinge pin is illustrated in the sectional view of'the housing as shown in Fig.1, it isto be understood that there are two hinge pins carried by two projections 25' rigidly secured to the housing in spaced apart relation. Element 26 of the toggle mechanism has pins 35 which engage openings 36 in the members 30 to provide pivotal connection between the two elements .24 and 26. Spring 21 is fastened at one end to brace member 32 carried by element 24 and at the other end of the toggle to the collapsed state illustrated in Fig. 5. The spring 21 when totally collapsed serves to prevent further collapse of the toggle mechanism. Element 26 has mounted on the free end thereof a contact 38 which is arranged to engage fixed contact i2 for the electrical connection of the lower end of the fuse l4 in a manner to be described. Element 28 is provided with an opening 40 for receiving the fuse tube H and is adapted to be fastened rigidly upon the tube in a suitable mannor as by means of a screw 4| which engages the screw threaded opening 42 in the element 28. Element 28 has also a projecting portion 43 which carries pins or studs 44 and 45 which slidably engage elongated slots 46 and 41 respectively in the plates 30 to thereby effect a pivotal connection between the fuse tube l4 and the element 24 of the toggle mechanism, it being understood that similar pins and slots are provided on the side of the toggle mechanism opposite to that shown in Fig. 5. Each of the slots 41 is formed to provide two communicating sections, the first of which, designated 48, has a lower edge which curves upwardly and outwardly as viewed when the toggle element 24 is in the vertical position illustrated in Fig. 1, and the second of which sections, designated 49, extends downwardly at an angle to the section 48. The spacing of pins :4 and 45 and the arrangement of slots 46 and i are such that when pins 45 slide outwardly and upwardly in sections 48 of slots 41, pins 44 at the same time slide upwardly in slots 46 until pins 45 reach the beginning of sections 49 of slots 41, whereupon pins 44 cease their upward travel substantially at the top of slots 46 and further outward movement of pins 45 into sections 49 produces a. counter-clockwise pivoting of the fuse tube with respect to element 24 about pins 44.

As best shown in Fig. 1, the hinged element or lever arm 24 of the fuse supporting toggle mochanism is arranged to be latched normally in rigid engagement with the lower end of fuse tube I! by means of the conductor 20 which is securely clamped to the strap 33 by means of winged clamping screw 50 whichscrews into a collar 5|) carried by the strap. Under these conditions the lower end of the tube i1 presses tightly against the strap. Clamping'screw 50 serves also to maintain in tight engagement with the conductor 20 one end of a highly conductive flexible and resilient metallic strip 5|, the other end of which strip is connected to contact 38 to insure good electrical connection between that contact and the lower end of the fuse to thereby mini mlze current flow through either the spring 21 or the elements of the toggle mechanism. The resiliency of strip 5| and the manner of bending the strip around the lower end of the toggle element 26 serves to exert a force which is in opposition to but considerably less than the force eicerted by spring 21 when under tension. The force of the strip is not suflicient to prevent the action of the spring to collapse the toggle mechanism but acts when the spring is in the collapsed state illustrated in Fig. 5 to exert a force sunlcient to maintain the ends of the spring in secure engagement with the brace member 32 and the element 26.

The projections 25', which are secured to the housing I0 and carry the hinge pins 25, have integrally formed abutments 54 which are ar-- ranged to engage the lower ends of the members 30 when the fuse l4 and door l3 swing into their horizontal positions illustrated in Fig. 4,

aosrei thus preventing further downward swinging of the fuse and door to a point at which the hookshaped portions 34 of the members 30 might become disengaged from the hinge pins 25.

To theback of the housing Hi there is secured a mounting bar 55 for the attachment of the cutout to a suitable supporting structure not shown. For manual operation of the cutout, cover l3 is-provided with a handle 56 which may be either grasped manually or engaged by a suitable form of switch stick to swing the fuse and door assembly inwardly and outwardly about the hinge pins 25.

In order to assemble the cutout for operation, cover I3 is mounted on the fuse M by passing the fuse tube I! through the openings provided in the projections I5 and IS on the back of the cover, element 28 being at the same time assembled on the fuse tube in such a manner that it is disposed intermediate the projection IB and the stop 29. The toggle mechanism may be attached to element 28, either before or after assembly of that element on the fuse tube, by placing the toggle arm 24 so that plates 30 are disposed on either side of the projection 43 of element 28 and inserting the pins 44 and 45 through slots 46 and 41 respectively into openings provided in the projection 43. Toggle arm'24 is then latched in engagement with the lower end of the fuse tube as previously described by screwing wing screw 5|) down tightly upon the end of conductor 20. So long as the fuse link connected to conductor 20 remains intact, the lower end of the fuse tube is latched firmly in engagement with the strap 33 of the toggle arm or lever 24 and pins 44 and 45 repose respectively in the lower ends of slots 46 and the inner ends of slots 41 as shown in Fig. 1.

Fuse l4 and its attached toggle mechanism, which is held in collapsed state by spring 21, are mounted in the housing by hooking the portions 34 of members 30 over the hinge pins 25 and then manually swinging the rigidly connected fuse tube IT and toggle arm 24 upwardly as a unit about the hinge pins and forcing the contact cap l8 into engagement with contact finger 2|. During the upward swinging of the fuse tube, contact 38 comes into engagement with the bearing surface of lower fixed contact l2 and slides upwardly thereon to the position indicated in Fig. 1, the element 26 of the toggle being forced into its extended position to place spring 21 under tension. With the spring under tension and fuse contact cap IS in engagement with contact finger 2|, the action of the spring tends to force the hingedly mounted lever arm 24 and the fuse tube il outwardly, but the combined action of seat 23 of the cont-act finger 2| and of resilient backing strip 22 serves to latch the upper end of the fuse from swinging outwardly about the hinge pins while the lower end of the fuse is latched in its inward position by means of conductor 20 and clamping screw 59. The lower latch remains operative as long as the fuse link remains intact and the fuse is held thereby in its inward position connected between fixed contacts H and I2, the connection at the upper end being through contact finger 2| to contact cap l8 and at the lower end through contact 38 and strip 5| to the conductor 20. While the fuse is in this connected position, cover' |3 effectively closes the open side of housing ID to thereby protect the fuse and its supporting and operating mechanism from adverse weather conditions. If it is de sired to open the cutout while the fuse link remains intact, it is necessary to grasp the handle outwardly and downwardly until.it reaches the position shown in Fig. 4 or, if desired, until it reaches a position at which the portions 3d of the members til can. be disengaged from the hinge pins When the cutout is closed, that is, when-fuse id is in its normal connected position shown in Fig. l and spring it is under tension, operation of the fuse results in expulsion of conductor 2t from the lower end of fuse tube it and release oi the lower latching arrangement, whereupon toggle arm 26 is drawn downwardly by the spring to force lever arm 2% of the toggle to swing outwardly about hinge pins 25. Were it not for the form of slots ll and the engagement of pins d5:

, therewith, the lower end of the fuse tube would during this initial movement.

pivot about the pins M in slots it of the lever arm 2G and the fuse tube would at the same time move bodily downward under the combined action of gravity and the force of the outwardly and downwardly swinging lever arm 26. However, the form of the sections to of slots til acts to compensate for the tendency of the arm 26 to move' the fuse tube bodily downward and actually to prevent such bodily downward movement so that contact cap 08 is not disengaged from latching seat In effect the slot sections it serve as guideways to produce a substantially arcuate movement of the lower end of the fuse tubeso that the initial movement of the tube is limited to a counterclockwise pivoting of. the lower end of the tube about its upper end, and slots lli provide for lost motion between the fuse and lever arm An important advantage of this initial pivotal movement of the fuse tube without disengagement of contact cap it from contact finger 2G is that the time required for pins to, move from the inner ends the outer ends of the slot sections (it afiords the delay necessary to permit the complete interruption of the current fiow' solely within the iuse tube and the blowing of conductor 2t out of the lower end of the fuse tube before the fuse drops out from. between the fixed contacts. Consequently no arcing'occurs either between contact cap ill and contact finger 28 or between contact and con tact it, even though the fuse is moved-subsequently to a position completely disengaged from the fixed contacts.

lit there is desired only an indication of the operation of the fuse without a complete disconnection of the fuse from the stationary contacts-this may be accomplished by placing stops in openings 52 in the members 3t] to prevent pins 655 from passing from slot sections (it into slot sections it. As a result of this expedient, the fuse id and cover it supported thereby are allowed to move only to the positions illustrated in Fig. 2 wherein the lower ends of the fuse tube and cover protrude from the housing in to give positive indication of the operation of the fuse. The binding action oi pins 65 against stops and of pins dd against the upper ends of slots 66 together wth the latching action. of the seat 2.5. prevents any further relative pivoting or the lever arm 2d and fuse tube it about their pivotal connection at pins dd, and the initial movement oi the fuse tube is insuficient to disengage the contact cap it from the latching seat While the fuse isin the indicating position or" Fig. 2, cover l3 stillprotects the parts of the cutout within the housing Ill from adverse weather conditions.

' Qnthe other hand, if complete dropout of the fuse is desired, it is necessary only to remove the pins 53 from the openings 52 so that outward swinging of toggle lever arm under the influence of spring Z'i can produce movement of the pins into slot sections 49. Under these circumstances, pins ld are restrained from further upward movement in slots 46 and the arrangement pf the slot sections 49 is such as to permit the fuse tube thunder the combined influence of gravity and the downward swinging of lever arm 2G, to move bodily downward to the intermediate position illustrated in Fig. 3 wherein contact cap it is shown as having dropped out of engagement with the latching seat 'As soon as the fuse tube ill and cover it reach the positions shown in Fig. 3, they are free to pivot outwardly and downwardly about pins 4d while the lever arm 2d of the toggle mechanism swings outwardly and downwardly about hinge pins When the lever arm, the fuse and the door. reach the positions illustrated in Fig. 4, fur; ther downward swinging or the lever arm is prevented by engagement thereof with the stops 5G while further downward swinging of the fuse and cover is prevented by theengagment oi the lower end of the fuse tube it with the strap 33 carried by the lever arm. Under these conditions the fuse is completely disconnected from the fixed contacts and is in a position which gives a clear indication of the operation of the fuse and permits ready removal of the fuse with its connected'door and toggle mechanism from the housing ill for servicing.

When the cutout is in the complete dropped out state illustrated in Fig; 4, the elements 2 1 and Eli of the toggle mechanism are prevented from further collapse by the combined action of the spring it in its compressed state and the resilient flexible strip at and hence the two elements are maintained sumciently spread apart so that the ends oi the spring cannot become disengaged from the brace member and the element respectively. o l

The structure of lever arm it comprising two members rigidly braced in spaced apart substantially parallel relation and the hinged mounting of these two members on rigidly supported spaced apart hinge pins 25, and also the connection of element 26 to element 2d at two op--.

i. In an electric cutout, tl'iecombination of (55 spaced upper and lower contacts, a fuse, a lever hingedly mounted at one end and connected for supporting the fuse, means for holding the leverin a substantially upright position and. in rigid relation to the fuse, said holding means being releasable by operation voi theiuse, means for connecting the fuse between the contacts and including a latch for preventing swinging or the upper end of the fuse out of engagement with the upper contact, means operative upon release upper and lower spaced contacts, a fuse, means for connecting the fuse between the contacts including a latch for holding the upper end of the fuse from swinging outwardly from engagement with the upper contact, and lever mechanism supporting said fuse and including means eifective upon operation of the fuse for causing an initial outward swinging movement of the lower end of the fuse about the upper end thereof without disengagement of said upper end from the upper contact,said lever mechanism including also means operative subsequently to said initial movement for effecting bodily movement of the fuse to disengage the upper end thereof from the upper contact.

3. In an electric cutout, the combination of spaced contacts, a fuse normally connected be tween the contacts, means effective upon operation of the fuse for actuating one end of the fuse towards its disconnected position, means for restraining the other end of the fuse in its connected position, and supporting means for the fuse having curved guideways slidably connected with the fuse and operative to limit the initial movement of said one end of the fuse to a substantially pivotal movement about said other end of the fuse.

4. In an electric cutout the combination of spaced contacts, a fuse, means for connecting the fuse between the contacts, means tending to force the fuse out of its connected position, means for latching the fuse in its connected position against the action of said forcing means and arranged to be released by operation of the fuse, a stud member secured to and projecting outwardly from the fuse, a supporting device for the fuse having an elongated slot arranged to receive said stud member to guide the fuse in its outward movement, and stop means removably secured to said supporting device at a predetermined ppint for engaging said stud member to limit the travel thereof in said slot.

5.'In an electric cutout, the combination of a mounting base, spaced contacts carried by the base, a fuse,means for connecting the fuse between the contacts, means for movably mounting the fuse on the base comprising a pair of elements attached respectively to the base and to the fuse and pivotally and slidably connected for relative movement with respect to each other, means for latching one end of the fuse in its connected position, means for latchingthe other end of the fuse in its connected position and released by operation of the fuse, and means operative upon release of said last mentioned latch ing means for effecting outward movement of saidother end of the fuse toward disconnecting position, said two mounting elements having means cooperative to restrict the initial movement of said other end of the fuse to substantially pivotal movement about said one end of the fuse and cooperative also to provide continuous support for, the fuse.

6. In an electric cutout, the combination of spaced contacts, a fuse normally connected between the contacts, latching -means normally holding one end" of the fuse in its connected position. means for movably Supporting the fuse including a supporting element having elongated slots and a second element rigidly attached to the fuse and having meansslidable in said slots, and means released by operation of the fuse for effecting movement of the fuse, said slots being formed to continuously engage said slidable means to provide continuous support for the fuse and having portions formed to guide the slidable means initially in a manner to produce pivotal movement of the fuse substantially about said one end and other portions formed at such angles to said first portion as to guide said slidable means subsequently in a manner to produce, bodily movement of the fuse to disengage said one end thereof from said latching means.

7. In an electric cutout, the combination of spaced contacts, a fuse normally connected between the contacts, a hingedly mounted lever arm pivotally connected to the fuse for movably supporting the same, means normally operative for holding the lever arm in rigid relation to the fuse with the fuse in connected position, said holding means being releasable by operation of the fuse, means operative upon release of said holding means for effecting movement of the fuse, means providing for lost motion between the lever arm and the fuse, and guide means carried'by the lever arm and operatively connected to the fuse for restraining one end of the fuse to pivot substantially about the other end thereof upon release of said holding means.

8. The combination of spaced contacts, a fuse,

a hingedly mounted lever arm pivotally connected to the fuse for supporting the same,

fuse from swinging out of engagement with one.

of the contacts, and means operative upon release of said holding means for exerting force tending to move the fuse towards its disconnecting position, said lever arm having an elongated slot providing for lost motion between the fuse and lever arm and having a second elongated slot operatively connected for controlling the movement of the fuse, said second slot having a first portion formed to. produce an initial substantially arcuate movement of the other end of the fuse, about said one end and to prevent bodily movement of the fuse to disengage said one end from said one'contact during such initial movement and having a second portion formed to provide for a subsequent bodily movement of the fuse to a totally disconnected position.

9. In an electric cutout the combination with spaced contacts and a fuse normally connected between the contacts, of means, for rigidly supporting the fuse including a lever arm having two portions extending in substantially parallel rigidly spaced apart relation and formed for the hinged mounting of the lever arm, fixedly mounted hinge supportingmeans arranged for the connection of said two portions of the lever arm thereto at spaced apart points, said lever arm having also two substantially parallel rigidly braced apart-portions arranged to extend on opposite sides of the fuse, and an element secured to the fuse and having pivot pins engaging openings provided in the last mentioned two portions of the leverarm.

BENJAMIN R. HERMANN. 

